TOF camera device and method of driving the same

ABSTRACT

A time of flight (TOF) camera device and a method of operating the same is provided. The time of flight (TOF) camera device includes a pulse generator configured to generate a pulse signal, a light module configured to emit output light to at least one object in response to the pulse signal, a three-dimensional (3D) sensor configured to receive reflected light when the output light is reflected by the at least one object for a first frame, a distance calculator configured to receive an output of the 3D sensor and generate a distance data signal, and a light density control device configured to receive the distance data signal from the distance calculator and output a light density control signal. The light density control signal may adjust the size of an opening in the light module to change a projected area from the output light onto the at least one object.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC § 119 to Korean PatentApplication No. 10-2020-0172917 filed on Dec. 11, 2020 in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a time of flight (TOF) camera deviceand a method of driving the same.

DISCUSSION OF THE RELATED ART

A time of flight (TOF) camera may detect the distance of an object fromthe camera by measuring a phase delay in the light emitted from thecamera and bounced off the object. For example, some conventional TOFcameras may modulate a light source with a predetermined frequency, emitthe modulated light onto a scene, and measure the phase shift of thelight reflected back into the camera in order to generate a depth map ata resolution determined by the camera's design. These types of camerasare widely used in the topographic surveying and object attitude controlfields.

SUMMARY

Embodiments of the present disclosure provide a time of flight (TOF)camera device configured to accurately identify a position of an objectby controlling light density.

Embodiments of the present disclosure also provide a method of drivingthe TOF camera device configured to accurately identify a position of anobject by controlling light density.

Aspects of the present disclosure are not necessarily limited to thoseset forth herein, and other aspects of the present disclosure will beapparent to those skilled in the art from the following description.

According to an aspect of the present disclosure, a time of flight (TOF)camera device includes: a pulse generator configured to generate a pulsesignal, a light module configured to emit output light to at least oneobject in response to the pulse signal, a three-dimensional (3D) sensorconfigured to receive reflected light when the output light is reflectedby the at least one object for a first frame, a distance calculatorconfigured to receive an output of the 3D sensor and generate a distancedata signal, and a light density control device configured to receivethe distance data signal from the distance calculator and output a lightdensity control signal, where the light density control signal controlsthe size of an opening within the light module through which the outputlight is emitted to determine a size of a projected area on the at leastone object, and where the light module emits the output light to the atleast one object for the first frame, wherein the output light has alight density corresponding to the light density control signal.

According to an aspect of the present disclosure, a method of driving atime of flight (TOF) camera device includes: generating a pulse signal,emitting output light to at least one object in response to the pulsesignal, receiving reflected light when the output light is reflected bythe at least one object for a first frame, generating a distance datasignal from the received reflected light and receiving the distance datasignal and outputting a light density control signal allowing a size ofan area, to which the output light is emitted to the at least oneobject, to be determined based on the distance data signal.

According to an aspect of the present disclosure, a method of driving atime of flight (TOF) camera device includes: emitting, by a lightmodule, first output light to a first area of a first object for a firstframe, changing an area, to which the first output light is emitted tothe first object, from the first area to a second area based on firstreflected light reflected by the first object for the first frame,emitting, by the light module, second output light to a third area of asecond object for a second frame subsequent to the first frame andchanging an area, to which the second output light is emitted to thesecond object, from a third area to a fourth area based on secondreflected light reflected by the second object for the second frame,wherein a size of the second area is different from a size of the fourtharea.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present disclosure willbecome more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings, in which:

FIG. 1 is a block diagram illustrating a time of flight (TOF) cameradevice.

FIG. 2 is a diagram illustrating an optical area of an object accordingto a size of an opening of a light density controller (LDC) according tosome embodiments.

FIG. 3 is a diagram illustrating an optical area of an object accordingto a size of an opening of an LDC according to some embodiments.

FIG. 4 is a diagram illustrating an optical area of an object accordingto a size of an opening of an LDC according to some embodiments.

FIG. 5 illustrates an example process of generating a 3D depth map froma 3D sensor according to some embodiments.

FIG. 6 illustrates an example process of generating a 3D depth map froma 3D sensor according to some embodiments.

FIG. 7 is a flowchart of a method of driving the TOF camera device.

FIG. 8 is a diagram illustrating an optical area of a first object andan optical area of a second object according to a size of the opening ofthe LDC according to some embodiments.

FIG. 9 illustrates example depth maps of the first object and the secondobject according to some embodiments.

FIG. 10 is a diagram illustrating a case in which the first object ofFIG. 8 is selected.

FIG. 11 is a diagram illustrating an optical area of the first objectand an optical area of the second object according to FIG. 10 .

FIG. 12 is a diagram illustrating a case in which the second object ofFIG. 8 is selected.

FIG. 13 is a diagram illustrating an optical area of the first objectand an optical area of the second object according to FIG. 12 .

FIG. 14 is a flowchart of a method of driving the TOF camera deviceaccording to some embodiments.

FIG. 15 is a diagram illustrating optical areas of a first object and asecond object according to a size of the opening of the LDC according tosome embodiments.

FIG. 16 is a diagram illustrating a state in which output light isemitted to the first object for a first frame.

FIG. 17 is a diagram illustrating an optical area of the first objectaccording to FIG. 16 .

FIG. 18 is a diagram illustrating a state in which the output light isemitted to the second object for a second frame.

FIG. 19 is a diagram illustrating an optical area of the second objectaccording to FIG. 18 .

FIG. 20 is a diagram illustrating a computer system including the TOFcamera device illustrated in FIG. 1 according to some embodiments.

FIG. 21 is a diagram illustrating a computer system including the TOFcamera device illustrated in FIG. 1 according to some embodiments.

FIG. 22 is a diagram illustrating a computer system including the TOFcamera device illustrated in FIG. 1 according to some embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be describedwith reference to the accompanying drawings. Like reference symbols inthe drawings may denote like elements, and to the extent that adescription of an element has been omitted, it may be understood thatthe element is at least similar to corresponding elements that aredescribed elsewhere in the specification.

In conventional phase detection TOF cameras, the accuracy of the TOFcamera depends on the modulation frequency, dynamic range, sensitivity,and other properties of the emitted light. Further, if the phase shiftis large enough from a very far object, then it may not be possible todetermine the distance to the object, as the measured range isdetermined by a modulo operation on the carrier wavelength (e.g., thephase shift may be large enough that it shifts beyond a full wavelength,yielding an uninterpretable result). In conventional phase detection TOFcameras where the modulation frequency is fixed, it may not be possibleto secure accurate results beyond a fixed distance.

The TOF camera device and systems described herein may accurately trackthe distance of multiple objects over time. Specifically, a TOF cameradevice according to embodiments of the present disclosure may include alight density control device, which may be configured to determine thedistance of one or more objects, and adjust a projected angle of lightwhich determines a corresponding optical area onto the one or moreobjects, thereby tracking the one or more objects across a wide distancerange with increased accuracy.

FIG. 1 is a block diagram illustrating a time of flight (TOF) cameradevice. FIG. 2 is a diagram illustrating an optical area of an objectaccording to a size of an opening of a light density controller (LDC)according to some embodiments. FIG. 3 is a diagram illustrating anoptical area of an object according to a size of an opening of an LDCaccording to some embodiments. FIG. 4 is a diagram illustrating anoptical area of an object according to a size of an opening of an LDCaccording to some embodiments.

Referring to FIG. 1 , a TOF camera device 100 may include a light module110, a light density control device 120, a distance calculator 130, athree-dimensional (3D) sensor 140, a memory device 150, an image signalprocessor (ISP) 160, and a pulse generator 170.

The light module 110 may include a light source 111 and an LDC 112. Thelight source 111 may emit output light OL to an object OJ in response toa pulse signal P generated by the pulse generator 170.

The LDC 112 may control an opening thereof, through which the outputlight OL is emitted, in response to a light density control signal LCONgenerated by the light density control device 120. For example, the LDC112 may control the size of the opening, through which the output lightOL is emitted, in response to the light density control signal LCONaccording to a position of the object OJ.

Referring to FIG. 2 , the light module 110 may emit the output light OLto the object OJ. In this case, a gap of the LDC 112 may be a first gapd1. In addition, the light module 110 may project the output light OLonto the object OJ over an area of the object; this projected area maybe referred to as an optical area, and may be a first area S11.

Referring to FIG. 3 , the light density control signal LCON may bechanged. In the example illustrated in FIG. 3 , the distance between thelight module 110 and the object OJ may be less than the distance of theexample illustrated in FIG. 2 . Further, the LDC 112 may increase a sizeof the opening of the LDC 112 in response to the light density controlsignal LCON. The LDC 112 may control the size of the opening, throughwhich the output light OL is emitted, in response to the light densitycontrol signal LCON.

In FIG. 3 , a gap of the LDC 112 may be a second gap d2, and a size ofthe second gap d2 may be greater than the first gap d1 (see FIG. 2 ).

As a result, the optical area of the output light OL emitted onto theobject OJ may be increased. For example, a size of the optical area ofthe output light OL emitted onto the object OJ may be increased from thefirst area S11 (see FIG. 2 ) to a second area S12.

Conversely, referring to FIG. 4 , a distance between the light module110 and the object OJ may be a distance greater than the distancebetween the light module 110 and the object OJ as illustrated in FIG. 2, and a size of the opening of the LDC 112 may be decreased in responseto the light density control signal LCON.

In FIG. 4 , a gap of the LDC 112 may be a third gap d3. A size of thethird gap d3 may be smaller than the size of the first gap d1. The sizeof the third gap d3 may be smaller than the size of the second gap d2.

As a result, an optical area of the output light OL emitted onto theobject OJ may be decreased. For example, a size of the optical area, towhich the output light OL is emitted onto the object OJ may be decreasedfrom the first area S11 (see FIG. 2 ) to a third area S13.

As described above, the size of the optical area of the output light OLemitted onto the object OJ may be changed according to the size of theopening of the LDC 112.

Further referring to FIG. 1 , the output light OL may have a constantfrequency. For example, a light source in an infrared light wavelengthrange may be used in the light module 110, but the embodiments are notnecessarily limited thereto.

The output light OL emitted to the object OJ may be reflected andreceived by the 3D sensor 140. A phase of reflected light RL reflectedby the object OJ may be changed with reference to the phase of theoutput light OL.

For example, when the phase of the reflected light RL is compared with aphase of the output light OL emitted by the light source 111, the phaseof the reflected light RL may be changed according to the distance tothe object OJ.

The 3D sensor 140 may receive the reflected light RL, which is theoutput light OL reflected by the object OJ, for a first frame. The 3Dsensor 140 may store phase difference information about the reflectedlight RL in the memory device 150.

The 3D sensor 140 may generate time information of the receivedreflected light RL from the phase difference information between theoutput light OL of the light module 110 and the reflected light RLreflected by the object OJ. From the time information, the 3D sensor 140may generate a 3D depth map DM of the object OJ.

A description of the 3D sensor 140 for generating the 3D depth map DMwill be described below with reference to FIGS. 5 and 6 .

The distance calculator 130 may receive an output of the 3D sensor 140to generate a distance data signal DCON. In this case, the output of the3D sensor 140 may be, for example, the 3D depth map DM.

The distance data signal DCON may be a signal based at least in part onthe time information between the output light OL and the reflected lightRL.

The light density control device 120 may receive the distance datasignal DCON from the distance calculator 130 and output the lightdensity control signal LCON in response. The light density controlsignal LCON may determine a size of an area to which the output light OLemitted by the light module 110. For example, the light density controlsignal LCON may determine the size of a gap in the LDC 112, therebyprojecting the output light OL onto the object OJ in an area, where thearea has a size determined by the gap in the LDC 112.

The light density control device 120 may receive the distance datasignal DCON to generate the light density control signal LCON. The lightdensity control signal LCON may allow the size of the opening, throughwhich the output light OL of the LDC 112 is emitted, to be adjusted.

The memory device 150 may store information received from the 3D sensor140. The memory device 150 may transmit the 3D depth map DM, an image,and the phase difference information generated by the 3D sensor 140 tothe ISP 160.

The ISP 160 may calculate a distance between the object OJ and the TOFcamera device 100 using the phase difference information. The ISP 160may transmit calculated information or the image to a display device200. The display device 200 may then display the image.

FIG. 5 illustrates an example process of generating a 3D depth map froma 3D sensor according to some embodiments. FIG. 6 illustrates an exampleprocess of generating a 3D depth map from a 3D sensor according to someembodiments.

Referring to FIG. 5 , the 3D sensor 140 may receive and combine rays ofreflected light RL reflected by the object to generate a 3D depth mapDM.

For example, the 3D sensor 140 may receive the rays of the reflectedlight reflected by the object OJ for a first frame. The 3D sensor 140may combine the rays of the reflected light to generate the 3D depth mapDM.

Referring to FIG. 6 , unlike FIG. 5 , the 3D sensor 140 may generate a3D depth map DM in which rays of reflected light RL reflected by theobject are successively combined.

For example, the 3D sensor 140 may receive multiple rays of thereflected light reflected by the object OJ for a first frame. The 3Dsensor 140 may successively combine the multiple rays of the reflectedlight to generate single rays SRL1 to SRLm of reflected light so as togenerate the 3D depth map DM.

FIG. 7 is a flowchart illustrating a method of driving the TOF cameradevice.

Referring to FIG. 7 , a pulse signal is generated (S100).

Referring to FIG. 1 , the pulse generator 170 may generate a pulsesignal P. Hereinafter, the method of driving the TOF camera deviceaccording to embodiments of the present disclosure will be describedusing the structure of the TOF camera device 100 described above.However, the embodiments are not necessarily limited thereto.

Next, output light is emitted to the object in response to the pulsesignal (S110).

Referring to FIG. 1 , the light module 110 may emit output light OL tothe object OJ in response to the pulse signal P generated by the pulsegenerator 170. For example, the light source 111 of the light module 110may emit the output light OL to the object OJ in response to the pulsesignal P.

Next, the reflected light reflected by the object is received by the 3Dsensor 140 (S120).

Referring to FIG. 1 , the 3D sensor 140 may receive the reflected lightRL reflected by the object OJ.

Next, a 3D depth map is generated using the received reflected light(S130).

Referring to FIG. 1 , the 3D sensor 140 may generate time information ofthe received reflected light RL on the basis of phase differenceinformation between the output light OL of the light module 110 and thereflected light RL reflected by the object OJ. The 3D sensor 140 maygenerate a 3D depth map DM of the object OJ from the time information.

Referring to FIG. 6 , in a case in which the 3D sensor 140 generates a3D depth map DM, multiple rays of reflected light RL reflected by theobject OJ may be successively combined to generate single rays SRL1 toSRLm of the reflected light so as to generate the 3D depth map DM. Forexample, the 3D depth map DM may be generated using the single rays SRL1to SRLm of the reflected light for each of frames F1 to Fn.

Referring to FIG. 5 , in the case in which the 3D sensor 140 generates a3D depth map DM, the rays of reflected light reflected by the object OJmay be combined to generate the 3D depth map DM.

Next, a distance data signal is generated from the generated 3D depthmap (S140).

Referring to FIG. 1 , the distance calculator 130 may generate adistance data signal DCON. The distance calculator 130 may receive the3D depth map DM, output from the 3D sensor 140, to generate the distancedata signal DCON.

Finally, a light density control signal may be output which allows asize of an area to which the output light is emitted onto the object tobe determined using the distance data signal (S150).

Referring to FIG. 1 , the light density control device 120 may generatea light density control signal LCON. The light density control device120 may determine the size of the area to which the output light OLemitted by the light module 110 onto the object. The light densitycontrol device 120 may receive the distance data signal DCON and outputthe light density control signal LCON on the basis of the distance datasignal DCON.

Accordingly, the LDC 112 may adjust a size of the opening thereofthrough which the output light OL is emitted in response to the lightdensity control signal DCON. The output light OL corresponding to thelight density control signal DCON may be emitted to the object OJ.

In FIGS. 1 to 7 , the case in which one object OJ is present for thefirst frame has been described, and hereinafter, an example in which twoobjects are present for the first frame will be described. Hereinafter,descriptions of the same or similar components as those of FIGS. 1 to 7will be omitted or only briefly described, and differences therebetweenwill be mainly described.

FIG. 8 is a diagram illustrating an optical area of a first object andan optical area of a second object according to a size of the opening ofthe LDC according to some embodiments. FIG. 9 illustrates example depthmaps of the first object and the second object according to someembodiments. FIG. 10 is a diagram illustrating a case in which the firstobject of FIG. 8 is selected. FIG. 11 is a diagram illustrating anoptical area of the first object and an optical area of the secondobject according to FIG. 10 . FIG. 12 is a diagram illustrating a casein which the second object of FIG. 8 is selected. FIG. 13 is a diagramillustrating an optical area of the first object and an optical area ofthe second object according to FIG. 12 .

Referring to FIG. 8 , a first object OJ1 may be separated from the lightmodule 110 by a first distance D1, and a second object OJ2 may beseparated from the light module 110 by a second distance D2 greater thanthe first distance D1.

For a first frame, the light source 111 may emit output light OL to thefirst object OJ1 and the second object OJ2 in response to a pulse signalP. For example, the output light OL emitted by the light module 110 maybe emitted to both of the first object OJ1 and the second object OJ2.

In this case, an area to which the output light OL is emitted onto thefirst object OJ1 may be a first area 51, and an area to which the outputlight OL is emitted onto the second object OJ2 may be a second area S2.

The 3D sensor 140 may receive first reflected light RL1 when the outputlight OL is reflected by the first object OJ1, and may receive a secondreflected light RL2 when the output light OL is reflected by the secondobject OJ2 for the first frame. The 3D sensor 140 may combine a depth ofthe first object OJ1 and a depth of the second object OJ2 to generate a3D depth map OJS.

Referring to FIG. 9 , since the first object OJ1 is positioned at afirst distance D1, which is relatively closer to the light module 110than the second object OJ2, a depth map thereof may be generated with aflood depth. Since the second object OJ is positioned at a seconddistance D2, which is relatively farther from the light module 110 thanthe first object OJ, a depth map thereof may be generated with a spotdepth. When the depth of the first object OJ1 and the depth of thesecond object OJ are combined, a depth map DMS which is more precisethan the depth map with the spot depth of the second object may begenerated.

Referring again to FIG. 8 , the distance calculator 130 may receive a 3Ddepth map OJS in which the first object OJ1 and the second object OJ2are combined to generate a distance data signal DCON. The light densitycontrol device 120 may receive the distance data signal DCON and outputa light density control signal LCON on the basis of the distance datasignal DCON.

For example, when the first object OJ1 and the second object OJ2 arepresent, the light density control device 120 may select either of thefirst object OJ1 and the second object OJ2 and output the light densitycontrol signal LCON on the basis of the selected object for the firstframe.

Hereinafter, an example in which the light density control device 120selects the first object OJ1 and outputs a first light density controlsignal LCON1 on the basis of the first object OJ1 will be described withreference to FIGS. 10 and 11 .

Accordingly, an example in which optical areas to which output light OLis emitted onto the first object OJ1 and onto the second object OJ2 arechanged according to the first light density control signal LCON1, willbe described.

Referring to FIGS. 10 and 11 , the distance calculator 130 may receive a3D depth map DM1 generated by the 3D sensor 140 to generate a firstdistance data signal DCON1. Since the first object OJ1 is separated fromthe light module 110 by the first distance D1, the distance calculator130 may generate the first distance data signal DCON1.

The light density control device 120 may receive the first distance datasignal DCON1 generated by the distance calculator 130 and generate thefirst light density control signal LCON1. For example, the light densitycontrol device 120 may generate the first light density control signalLCON1 to correspond to the first distance data signal DCON1.

The first light density control signal LCON1 may be used to determinethe areas to which the output light OL is emitted by the light module110 onto the first object OJ1 and onto the second object OJ2 on thebasis of the first distance data signal DCON1.

The LDC 112 may adjust a size of the opening thereof through which theoutput light OL is emitted in response to the first light densitycontrol signal LCON1.

A gap of the opening of the LDC 112 due to the first light densitycontrol signal LCON1 may be a second gap d5. A size of the second gap d5may be greater than a first gap d4.

As described above, since the gap of the opening of the LDC 112 becomesthe second gap d5, an optical area, to which the output light OL isemitted onto the first object OJ1 may be changed to a third area S3. Forexample, the optical area, to which the output light OL is emitted ontothe first object OJ1 may be changed from the first area 51 to the thirdarea S3 according to the first light density control signal LCON1. Asize of the third area S3 may be greater than a size of the first area51.

Similarly, since the gap of the opening of the LDC 112 becomes thesecond gap d5, an optical area, to which the output light OL is emittedonto the second object OJ2 may be changed to a fourth area S4. Forexample, the optical area, to which the output light OL is emitted ontothe second object OJ2 may be changed from the second area S2 to thefourth area S4 according to the first light density control signalLCON1. A size of the fourth area S4 may be greater than a size of thesecond area S2.

Next, an example in which the light density control device 120 selectsthe second object OJ2 and outputs a second light density control signalLCON2 on the basis of the second object OJ2 will be described withreference to FIGS. 12 and 13 .

An example in which optical areas to which output light OL emitted ontothe first object OJ1 and the second object OJ2 are changed according tothe second light density control signal LCON2 will now be described.

The distance calculator 130 may receive a 3D depth map DM2 generated bythe 3D sensor 140 to generate a second distance data signal DCON2. Sincethe second object OJ2 is separated from the light module 110 by a seconddistance D2 which is greater than a first distance D1, the distancecalculator 130 may generate the second distance data signal DCON2.

The light density control device 120 may receive the second distancedata signal DCON2 generated by the distance calculator 130 to generatethe second light density control signal LCON2. For example, the lightdensity control device 120 may generate the second light density controlsignal LCON2 to correspond to the second distance data signal DCON2.

The second light density control signal LCON2 may be used to determinesizes of the areas to which the output light OL is emitted by the lightmodule 110 is emitted onto the second object OJ2 and the first objectOJ1 on the basis of the second distance data signal DCON2.

The LDC 112 may adjust a size of the opening, through which the outputlight OL is emitted, in response to the second light density controlsignal LCON2.

In response to the second light density control signal LCON2, a gap ofthe opening of the LDC 112 may become a third gap d6. A size of thethird gap d6 may be smaller than the size of the first gap d4 (see FIG.10 ).

Accordingly, since a size of the opening of the LDC 112 becomes thethird gap d6, an optical area, to which the output light OL is emittedonto the second object OJ2 may be changed to a sixth area S6. Theoptical area, to which the output light OL is emitted onto the secondobject OJ2 may be changed from the second area S2 to the sixth area S6according to the second light density control signal LCON2. The sixtharea S6 may be smaller than the second area S2. In other words, thesecond area S2 may be greater than the sixth area S6.

Similarly, since the size of the opening of the LDC 112 becomes thethird gap d6, an optical area, to which the output light OL is emittedonto the first object OJ1 may be changed to a fifth area S5. The opticalarea, to which the output light OL is emitted onto the first object OJ1may be changed from the first area 51 to the fifth area S5 according tothe second light density control signal LCON2. The fifth area S5 may besmaller than the first area 51. In other words, the first area 51 may begreater than the fifth area S5.

FIG. 14 is a flowchart illustrating a method of driving the TOF cameradevice according to some embodiments. FIG. 15 is a diagram illustratingoptical areas of a first object and a second object according to a sizeof the opening of the LDC according to some embodiments. FIG. 16 is adiagram illustrating a state in which output light is emitted to thefirst object for a first frame. FIG. 17 is a diagram illustrating anoptical area of the first object according to FIG. 16 . FIG. 18 is adiagram illustrating a state in which the output light is emitted to thesecond object for a second frame. FIG. 19 is a diagram illustrating anoptical area of the second object according to FIG. 18 .

Referring to FIG. 14 , for the first frame, first output light isemitted to the first object by the light module (S200).

Referring to FIG. 15 , for the first frame, a first object OJ3 may bedisposed at a position separated from the light module 110 by a firstdistance D1.

The light source 111 of the light module 110 may emit first output lightOL3 to the first object OJ3. In this case, a gap of the opening of theLDC 112 through which the first output light OL3 is emitted may be afirst gap d7. An area, to which the first output light OL3 is emittedonto the first object OJ3 may be a first area S6.

Next, for the first frame, the area, to which the first output light isemitted onto the first object is changed from the first area to a secondarea on the basis of first reflected light reflected by the first object(S210).

Referring to FIGS. 16 and 17 , the 3D sensor 140 may receive firstreflected light RL3 reflected by the first object OJ3. The 3D sensor 140may generate a third 3D depth map DM3 on the basis of the firstreflected light RL3. Since a description of the generation of the third3D depth map DM3 by the 3D sensor 140 generating has been described withreference to FIGS. 5 and 6 , the specific description thereof will beomitted.

The distance calculator 130 may receive the third 3D depth map DM3generated by the 3D sensor 140 to generate a third distance data signalDCON3. The light density control device 120 may receive the thirddistance data signal DCON3 to output a third light density controlsignal LCON3.

The third light density control signal LCON3 may allow a size of thearea, to which the first output light OL3 emitted by the light module110 is emitted onto the first object OJ3 to be determined.

The gap of the opening of the LDC 112 may be adjusted in response to thethird light density control signal LCON3. For example, the gap of theopening of the LDC 112 may be changed from the first gap d7 to a secondgap d8. A size of the first gap d7 may be smaller than a size of thesecond gap d8. The size of the second gap d8 may be greater than thesize of the first gap d7.

Since the gap of the opening of the LDC 112 is changed, the area, towhich the first output light OL3 is emitted onto the first object OJ3may be changed from a first area S7 to a second area S8. A size of thefirst area S7 may be smaller than a size of the second area S8.

Next, referring to FIG. 14 , for the second frame subsequent to thefirst frame, second output light is emitted to a third area of thesecond object by the light module (S220).

Referring to FIGS. 15 and 18 , for the second frame, a second object OJ4may be disposed at a position separated from the light module 110 by asecond distance D2. The second distance D2 may be different from thefirst distance D1. For example, the second distance D2 may be greaterthan the first distance D1.

The light source 111 of the light module 110 may emit second outputlight OL4 to the second object OJ4. In this case, the gap of theopening, through which the second output light OL4 is emitted, of theLDC 112 may be the first gap d7. An area, to which the second outputlight OL4 is emitted onto the second object OJ4 may be a third area S9.

Finally, for the second frame, the area, to which the second outputlight is emitted onto the second object is changed from the third areato a fourth area on the basis of second reflected light reflected by thesecond object (S230).

Referring to FIGS. 18 and 19 , for the second frame, the 3D sensor 140may receive second reflected light RL4 reflected by the second objectOJ4. The 3D sensor 140 may generate a fourth 3D depth map DM4 on thebasis of the second reflected light RL4. Since a description of thegeneration of the 3D depth map DM by the 3D sensor 140 has beendescribed with reference to FIGS. 5 and 6 , redundant descriptionthereof will be omitted.

The distance calculator 130 may receive the fourth 3D depth map DM4generated by the 3D sensor 140 to generate a fourth distance data signalDCON4. The light density control device 120 may receive the fourthdistance data signal DCON4 to output a fourth light density controlsignal LCON4.

The fourth light density control signal LCON4 may allow a size of thearea, to which the second output light OL4 emitted by the light module110 is emitted onto the second object OJ4 to be determined.

The gap of the opening of the LDC 112 may be adjusted in response to thefourth light density control signal LCON4. For example, the gap of theopening of the LDC 112 may be changed from the first gap d7 to a secondgap d9. The size of the first gap d7 may be greater than a size of thesecond gap d9.

Since the gap of the opening of the LDC 112 is changed, the area, towhich the second output light OL4 is emitted onto the second object OJ4may be changed from the third area S9 to a fourth area S10 The size ofthe fourth area S10 may be smaller than the size of the third area S9.

Accordingly, the size of the second area S8, to which the second outputlight OL4 is emitted onto the first object OJ3 for the first frame andthe size of the fourth area S10, to which the second output light OL4 isemitted onto the second object OJ4 for second frame may be different.The size of the fourth area S10 may be smaller than the size of thesecond area S8.

FIG. 20 is a diagram illustrating a computer system including the TOFcamera device illustrated in FIG. 1 according to some embodiments.

Referring to FIG. 20 , a computer system 300 may be implemented as asmart phone, a personal digital assistant (PDA), a portable multimediaplayer (PMP), a Moving Picture Experts Group (MPEG)-3 Audio Layer 3(MP3) player, an MPEG-4 Part 14 (MP4) player, or the like.

The computer system 300 may include a memory device 301, an applicationprocessor (AP) 302 including a memory controller configured to controlthe memory device 301, a wireless transceiver 303, an antenna 304, aninput device 305, and a display device 306.

The wireless transceiver 303 may transmit or receive a wireless signalthrough the antenna 304. For example, the wireless transceiver 303 mayconvert the wireless signal received through the antenna 304 to a signalwhich may be processed by the AP 302.

Accordingly, the AP 302 may process the signal output from the wirelesstransceiver 303 and transmit the processed signal to the display device306. The wireless transceiver 303 may convert the signal output from theAP 302 to a wireless signal and output the converted wireless signal toan external device through the antenna 304.

The input device 305 may be a device through which a control signal forcontrolling the operation of the AP 302 or data to be processed by theAP 302 is input. In some embodiments, the input device 305 may beimplemented as a pointing device such as a touch pad or computer mouse,a keypad, or a keyboard.

In addition, the computer system 300 may further include a TOF cameradevice 307 for measuring a distance to an object and an image sensor 308for capturing still or moving images. The AP 302 may transmit the stillor moving images and distance information to the object received fromthe image sensor 308 to the display device 306.

For example, the TOF camera device 100 illustrated in FIG. 1 may beimplemented as the TOF camera device 307.

FIG. 21 is a diagram illustrating a computer system including the TOFcamera device illustrated in FIG. 1 according to some embodiments.

Referring to FIG. 21 , a computer system 400 may be implemented as apersonal computer (PC), a network server, a tablet PC, a net-book, or ane-reader.

The computer system 400 may include a memory device 401, an AP 402including a memory controller capable of controlling a data processingoperation of the memory device 401, an input device 405, and a displaydevice 406. For example, the computer system 400 may be similar to thecomputer system 300, but might not include a transceiver for radiocommunication.

The AP 402 may display data stored in the memory device 401 through thedisplay device 406 according to data input through the input device 405.For example, the input device 405 may be implemented as a pointingdevice such as a touch pad or a computer mouse, a keypad, or a keyboard.The AP 402 may control the overall operation of the computer system 400.

In addition, the computer system 400 may further include a TOF cameradevice 407 for measuring a distance to an object and an image sensor 408for capturing still or moving images. The AP 402 may transmit the stillor moving images and distance information to the object received fromthe image sensor 408 to the display device 406.

For example, the TOF camera device 407 may be implemented as the TOFcamera device 100 illustrated in FIG. 1 .

FIG. 22 is a diagram illustrating a computer system including the TOFcamera device illustrated in FIG. 1 according to some embodiments.

Referring to FIG. 22 , a computer system 500 may be implemented as animage processing device, such as a digital camera or a mobile phone, asmart phone, or a tablet to which a digital camera is attached.

The computer system 500 may include a memory device 501, an AP 502including a memory controller capable of controlling a data processingoperation such as a write operation or a read operation of the memorydevice 501, an input device 505, an image sensor 508, a display device506, and a TOF camera device 507. For example, the computer system 500may be similar to the computer system 400; however, the computer system500 may have a display device integrally formed within the system, andnot necessarily as an external component.

The image sensor 508 converts an optical image to digital signals, andthe converted digital signals are transmitted to the AP 502. Theconverted digital signals may be displayed through the display device506 or stored in the memory device 501 according to control of the AP502.

The TOF camera device 507 may measure a distance to an object. The AP502 may transmit distance information to the display device 506. Inaddition, the AP 502 may transmit image date stored in the memory device501 to the display device 506.

For example, the TOF camera device 507 may be implemented as the TOFcamera device 100 illustrated in FIG. 1 .

As is traditional in the field of the present invention, embodiments aredescribed, and illustrated in the drawings, in terms of functionalblocks, units and/or modules. Those skilled in the art will appreciatethat these blocks, units and/or modules are physically implemented byelectronic (or optical) circuits such as logic circuits, discretecomponents, microprocessors, hard-wired circuits, memory elements,wiring connections, etc., which may be formed using semiconductor-basedfabrication techniques or other manufacturing technologies. In the caseof the blocks, units and/or modules being implemented by microprocessorsor similar, they may be programmed using software (e.g., microcode) toperform various functions discussed herein and may optionally be drivenby firmware and/or software. Alternatively, each block, unit and/ormodule may be implemented by dedicated hardware, or as a combination ofdedicated hardware to perform some functions and a processor (e.g., oneor more programmed microprocessors and associated circuitry) to performother functions.

As described above, the TOF camera device and systems described hereinmay accurately track the distance of multiple objects over time.Specifically, a TOF camera device according to embodiments of thepresent disclosure may include a light density control device, which maybe configured to determine the distance of one or more objects, andadjust a projected angle of light which determines a correspondingoptical area onto the one or more objects, thereby tracking the one ormore objects across a wide distance range with increased accuracy.

What is claimed is:
 1. A time of flight (TOF) camera device comprising:a pulse generator configured to generate a pulse signal; a light moduleconfigured to emit an output light onto at least one object in responseto the pulse signal; a three-dimensional (3D) sensor configured toreceive reflected light when the output light is reflected by the atleast one object for a first frame; a distance calculator configured toreceive an output of the 3D sensor and generate a distance data signal;and a light density control device configured to receive the distancedata signal from the distance calculator and output a light densitycontrol signal, wherein the light density control signal controls a sizeof an opening within the light module through which the output light isemitted to determine a size of a projected area onto the at least oneobject, wherein the light module emits the output light to a first areaof the at least one object for the first frame, and wherein the lightdensity control signal changes the size of the opening of the lightmodule in response to the distance data signal to emit the output lightto a second area of the at least one object in a second frame, whereinthe second area is different from the first area.
 2. The TOF cameradevice of claim 1, wherein the 3D sensor is configured to: generate timeinformation of the received reflected light based on phase differenceinformation, wherein the phase difference information comprises adifference between a phase of the output light of the light module and aphase of the reflected light reflected by the object; and generate a 3Ddepth map of the object based on the time information.
 3. The TOF cameradevice of claim 2, wherein: the at least one object includes a firstobject separated from the light module by a first distance and a secondobject separated from the light module by a second distance greater thanthe first distance; and the 3D depth map is generated by combining adepth of the first object and a depth of the second object.
 4. The TOFcamera device of claim 2, wherein the 3D sensor generates the 3D depthmap by successively combining rays of reflected light reflected by theat least one object.
 5. The TOF camera device of claim 2, wherein the 3Dsensor generates the 3D depth map by combining rays of the reflectedlight reflected by the at least one object.
 6. The TOF camera device ofclaim 1, wherein: the light module includes a light density controller;and the light density controller adjusts the size of the opening,through which the output light is emitted, in response to the lightdensity control signal.
 7. The TOF camera device of claim 6, wherein thelight density controller adjusts the size of the opening from a firstsize to a second size smaller than the first size in response to thelight density control signal.
 8. The TOF camera device of claim 6,wherein: the at least one object includes a first object separated fromthe light module by a first distance and a second object separated fromthe light module by a second distance greater than the first distance;and the light density control device selects the first object or thesecond object and outputs the light density control signal based on theselected object.
 9. A method of driving a time of flight (TOF) cameradevice, comprising: generating a pulse signal; emitting output light ina first frame through an opening to a first area of at least one objectin response to the pulse signal, wherein a size of the openingdetermines a projected area of light on the at least one object;receiving reflected light when the output light is reflected by the atleast one object for the first frame; generating a distance data signalfrom the received reflected light; generating a light density controlsignal based on the distance data signal; changing the size of theopening through which the output light is emitted in a second framebased on the light density control signal; and emitting the output lightthrough the opening to a second area of the at least one object, whereinthe second area is different from the first area.
 10. The method ofclaim 9, further comprising: generating time information of the receivedreflected light based on phase difference information between the outputlight and the reflected light reflected by the at least one object; andgenerating a three-dimensional (3D) depth map of the at least one objectbased on the time information, wherein the distance data signal isgenerated based on the 3D depth map.
 11. The method of claim 10,wherein: the at least one object includes a first object separated froma light module by a first distance and a second object separated fromthe light module by a second distance greater than the first distance;and the 3D depth map is generated by combining a depth of the firstobject and a depth of the second object.
 12. The method of claim 10,wherein the generating of the 3D depth map of the at least one objectincludes successively combining rays of the reflected light reflected bythe at least one object to generate the 3D depth map.
 13. The method ofclaim 10, wherein the generating of the 3D depth map of the at least oneobject includes combining rays of the reflected light reflected by theat least one object to generate the 3D depth map.
 14. The method ofclaim 9, wherein the light density control signal based on the distancedata signal controls the size of the opening through which the outputlight is emitted.
 15. The method of claim 14, wherein the light densitycontrol signal allows the size of the opening to be adjusted from afirst size to a second size smaller than the first size.
 16. The methodof claim 14, wherein: the at least one object includes a first objectseparated from a light module by a first distance and a second objectseparated from the light module by a second distance greater than thefirst distance; and the outputting of the light density control signalincludes selecting the first object or the second object and outputtingthe light density control signal based on the selected object.
 17. Amethod of driving a time of flight (TOF) camera device, comprising:emitting, by a light module, first output light to a first area of afirst object for a first frame; changing an area, to which the firstoutput light is emitted to the first object, from the first area to asecond area based on first reflected light reflected by the first objectfor the first frame; emitting, by the light module, second output lightto a third area of a second object for a second frame subsequent to thefirst frame; and changing an area, to which the second output light isemitted to the second object, from a third area to a fourth area basedon second reflected light reflected by the second object for the secondframe, wherein a size of the second area is different from a size of thefourth area.
 18. The method of claim 17, wherein: the first object isdisposed at a position separated from the light module by a firstdistance; and the second object is disposed at a position separated fromthe light module by a distance different from the first distance. 19.The method of claim 17, wherein: a size of the first area is greaterthan the size of the second area; and a size of the third area isgreater than the size of the fourth area.
 20. The method of claim 17,wherein: the first object is disposed at a position separated from thelight module by a first distance; the second object is disposed at aposition farther from the light module than the first distance; and thesize of the fourth area is smaller than the size of the second area.